1. Field of the Invention
This invention relates to apparatus and method for setting toe on all four wheels of a four wheeled vehicle utilizing manually operable equipment.
2. Description of the Prior Art
In the past a manually operable wheel aligner called the Acraliner was used to first adjust a wheel pair at one end of a vehicle and then, after the vehicle had been turned end for end, to adjust the wheel pair at the other end of the vehicle. Caster, camber and toe were set by the Acraliner equipment. Aligner head mounting clamps were applied to the wheel rims at one end of the vehicle. The clamps carried a platform with manual adjustment structure so that the run-out or departure of the wheel rim from an average rotational plane could be adjusted out of the platform. A projection head was mounted to the platform projecting a light array either forwardly or rearwardly from the wheel on which mounted depending on the position to which the projection head was turned on the platform. A projection screen was formed on the projection head to receive reflected images of the light array projected therefrom. The caster and camber were adjusted in the wheel pair using apparatus and processes not pertinent to this disclosure. A mirror bar was mounted for movement in a panel situated proximate to the wheel pair being measured. The mirror bar was adjusted in position to intercept the light array from the projector head and thereby functioned to reflect the light array back to the screen formed on the projector head. Positionable targets were placed against wheels of the vehicle more distant from the panel and the direction of projection from the projector heads was reversed to impinge on the targets. The wheels closest to the panel were moved in steering until the zero mark in one light array intercepted the zero mark on the associated positionable target. A position of the index mark from the other light array on the other positionable target was noted and the wheels on which the light projectors were mounted were turned until the projected index marks indicated half of the last reading noted on each scale. The projectors were rotated to project the light arrays forwardly without moving the steerable wheels. The projected light arrays thereby were intercepted by the reflectors on the mirror bar so that a reflected light array was directed back to the projection screens on the projection heads. The mirror bar was then adjusted so that the toe readings were equal on each head target. The tie rods for the steerable wheels, preloosened so that accidental shifting of the steering would not occur, were then adjusted to obtain the proper toe on each wheel when the steering wheel was in the level or straight ahead driving position. As a general rule the toe was set with half of the total toe in the left hand wheel and half of the total toe in the right hand wheel for the straight ahead position.
Other prior art systems are known wherein a vertically oriented light stripe is projected instead of a light array or wherein an optical path may be viewed rather than projecting a light array. In such systems 4-wheel alignment requires that the wheel at one end of the vehicle be set in toe and the vehicle long axis then be reversed to set the other pair of wheels in toe.